Electromagnetic braking device for the ingot in a continuous casting unit

ABSTRACT

The invention relates to an electromagnetic braking device for the steel melt running within the continuous casting ingot in a continuous casting unit. The electromagnetic brake device comprises at least one coil ( 3 ) with a ferromagnetic core ( 5 ), arranged on the broad side of the ingot and at least one yoke ( 7 ) provided on the above. In order to reduce the oscillating masses on the ingot components and to permit the retro-fitting of electromagnetic brakes to conventional continuous casting machines, the electromagnetic brake, comprising yoke ( 7 ), coil ( 3 ) and ferromagnetic core ( 5 ), is embodied such as to pivot inwards or outwards, preferably by means of two unequal length, non-parallel levers in or on the continuous casting ingot, using an actuator ( 6 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage of PCT/EP02/10029 filed 7 Sep. 2002and based upon German national application 101 46 993.4 filed 25 Sep.2001 under the International Convention.

FIELD OF THE INVENTION

The invention relates to an electromagnetic braking device for the steelmelt which flows into the continuous casting mold of a continuouscasting apparatus and which comprises at least one coil juxtaposed witha broad side of the mold and having a ferromagnetic core and at leastone yoke juxtaposed or associated with the latter.

BACKGROUND OF THE INVENTION

Continuous casting plants of the type described at the outset are known.The casting stream flowing into the mold is braked by a magnetic fieldwhich is caused to be effective between the broad sides of thecontinuous casting mold to reduce the turbulence and to direct, orientor smooth out the casting stream. To generate the magnetic field,ferromagnetic cores are applied against the copper plates of the broadsides and coils surrounding the cores are electrically excited.Directing effects of the magnetic field upon the casting stream has theeffect of calming the steel bath and reducing the turbulence within thesteel bath with the goal of ensuring a uniform casting of the steelstrand.

In the state of the art, an integrated arrangement of the magneticbraking device is known, whereby the ferromagnetic coil and the coilthrough which the electric current flows are fixed on the mold.Depending upon the configurations of these components of the brakingdevice, the latter may have considerable weight which must be supportedby the lifting table of the mold and thus must be moved togethertherewith. It is a drawback of an integrated arrangement of the brakingdevice and the mold that the masses which must be oscillated with moldoscillation can be excessively high and, further, that the integratedarrangement contributes to increased changeover times for the couplingof water and electrical connections to the assembly and thedisconnection of those connections. In addition, the electromagneticbraking device can impede the requisite heat dissipation from the copperplates. Finally a relatively large number of electromagnetic brakes mustbe provided each mold in this configuration.

In the state of the art an external arrangement of an electromagneticbrake is also known in which the electromagnetic coil and the corethrough which the electric current flows are arranged to be movable inthe apparatus. With the external arrangement of the coil and core, themasses which have to be oscillated are thereby reduced. The changeovertime can be significantly reduced since the need for connecting anddisconnecting water and electrical fittings is eliminated. Finally thissystem requires only a small number of electromagnetic brake units,namely only a single electromagnetic brake per casting strand.

DE 198 07 842 A1 describes a continuous casting plant with anelectromagnetic braking device which is comprised of at least one coiljuxtaposed with a broad side of a casting mold with a ferromagnetic coiland at least one yoke juxtaposed therewith. At least some individualparts of the electromagnetic braking device are supporting members forthe continuous casting mold. The magnetic field generated by theelectromagnetic braking device is distributed with reference to thecontinuous casting mold into at least one upper magnetic field and alower magnetic field. At least the inner ones of the electromagneticcores form at the same time cooling chambers by means of which coolingwater can be supplied and the cooling water can be discharged. Throughthe integration of the electromagnetic braking device as supportingcomponents in the continuous casting mold, indeed there is a saving inweight, but nevertheless the mass which must be oscillated is relativelyhigh.

OBJECT OF THE INVENTION

The object of the invention is to improve upon the aforedescribedarrangements of electromagnetic brakes on continuous casting molds andespecially to avoid the tendency of tilting resulting from an axial feedthrough a slide or carriage guide arrangement which, in addition,requires sufficient place and contributes additional weight, and wherebythe retrofitting of an existing continuous casting apparatus with theimproved electromagnetic brake is facilitated or simplified.

SUMMARY OF THE INVENTION

The object achieved with an electromagnetic brake comprised of the yoke,the coil which can be traversed by an electric current and theferromagnetic core, and which is swingable in or on the continuouscasting mold by at least one positioning unit into and out of position.Preferably the mechanical swinging of the brake into position and out ofposition is effected by means of at least two nonparallel levers ofunequal length. As a result, in spite of the provision of a rail carrierfor the tundish carriage, the prerequisites for an optimal retrofittingof continuous casting plants with the brake device according to theinvention are satisfied.

In a refinement of the electromagnetic brake according to the inventionthe brake comprised of the yoke, the electric-current-traversed core andthe ferromagnetic core are not oscillatable together with the continuouscasting mold.

With the features according to the invention the advantage can beobtained that the electromagnetic brake independently of the continuouscasting mold is readily replaceable and that the oscillating masses oncomponents of the continuous casting mold remain limited and noadditional mass must be oscillated because of the components of theelectromagnetic brake.

According to another feature of the electromechanical brake according tothe invention, it is proposed to provide a magnetic partial core toreduce the pole spacing and to increase the effectivity of theelectromagnetic brake in magnetic water boxes.

BRIEF DESCRIPTION OF THE DRAWING

The invention is described in conjunction with an embodiment thereoffurther below, from which additional details and advantages of theinvention can be deduced. In the drawing:

FIG. 1 is a perspective view showing the working position of theelectromagnetic brake.

FIG. 2 is a perspective view showing the rest position of theelectromagnetic brake.

SPECIFIC DESCRIPTION

FIGS. 1 and 2 show the electromagnetic brake according to the inventioncomprised of a yoke 7, a coil 3 which is traversed by an electriccurrent and a ferromagnetic core 5. The electromagnetic brake is affixedby means of a mechanism having two pairs of unequal length, nonparallellevers 9, 10 on a rail carrier 11 and is displaceable by a positioningelement 6, for example a hydraulic cylinder, articulated to the centerthereof. On the one hand this enables a displacement of theelectromagnetic brake along a curve but with an approximately horizontalmovement thereof out of the water box 2 and the frame 1 of the mold 2.On the other hand it ensures a space-saving rest position for theelectromagnetic brake between the rail carrier 11 and the mold so thatthe replacement of the mold and the strand guide segments of thecontinuous casting apparatus is possible in a problem-free manner. Thisarrangement also ensures a small stroke as well as a smaller adjustmentforce than does a linear system for displacement of the electromagneticbrake since the system is located close to its upper dead point. Thecontinuous casting molds and the electromagnetic brake are independentcomponents so that in calculating the oscillating forces, exclusivelythe mass to be moved of the mold components need be considered. FIG. 1shows the electromagnetic brake in the working position. In the workingposition there is an adjustable stroke limiter 8 establishing theposition. FIG. 2 shows the rest position of the electromagnetic brake.In the rest position the brake lies against the abutments 4.

1. An electromagnetic brake device for a steel melt flowing into acontinuous casting mold of a continuous casting apparatus, theelectromagnetic brake device comprising: at least one coil juxtaposablewith a broad side of the mold; a ferromagnetic core for the coil; atleast one yoke (7) juxtaposed with the coil a mechanism having twounequal length nonparallel levers for swinging the yoke, coil andferromagnetic core, into position or out of position in or on thecontinuous casting mold and at least one positioning element fordisplacing said mechanism.
 2. The electromagnetic brake device accordingto claim 1 which is not oscillatable together with the continuouscasting mold.
 3. The electromagnetic brake device according to claim 1which has a working position established by a mechanical stroke limiteron the continuous casting mold.
 4. The electromagnetic brake deviceaccording to claim 1, wherein, for reducing a pole spacing andincreasing effectivity of the electromagnetic brake device in magneticwater boxes, a magnetic partial core is provided.
 5. The electromagneticbrake device according to claim 1 wherein the positioning element isformed by at least one hydraulic cylinder.
 6. The electromagnetic brakedevice according to claim 1 wherein a working position of theelectromagnetic brake device is determined by at least one adjustablestroke limiter.
 7. The electromagnetic brake device according to claim 1wherein said mechanism has a rest position determined by at least oneabutment 4.